"Etymology"
During the Spanish era, a small community in Northern Luzon was formed. Arguing on how and what name to call it, the dwellers agreed for the name “San Ildefonso”, after they saw an engraved statue of San Ildefonso placed inside the big wooden box floating along Bantaoay River. In his honor, the people decided to make him the Patron Saint of the place, and an annual town
fiesta celebration in his honor is held every January 23 in this town, the day when the image was found. "Creation of the Municipality"
San Ildefonso was established during the Spanish era in the year 1625. By virtue of Executive Order 19 - 1901 annexing smaller towns to adjacent bigger ones, San Ildefonso was annexed as a barrio to Sto. Through the help of the late President Elpidio Quirino, then an assemblyman, San Ildefonso was again made a separate town in 1920. No legal basis for the separation. "Socio Cultural Development"
San Ildefonso is inhabited by Christians who are mostly Ilocano, and few Tagalogs, Pangasinenses, Bicolanos and Visayas who migrated to the municipality through inter-marriages. Although the people are of different groups, they are basically industrious, hardworking, and frugal. Most of them are farmers. Education is of paramount importance to the people. The parents are willing to spend to provide education to their children because they adhere to the principle that the best heritage a parent can give to his children is education. People of the town are also gregarious and sociable to the extent that majority of the people know each other. They share each other joys and sorrows. In fact, during occasions like birthdays, death anniversaries / mourning, parties, Christmas and fiesta, people usually pay courtesy calls, attend and render assistance materially, physically, or financially to / with families and neighbors. In other words, there is unity and cooperation among residents. "Economic Development"
Since the beginning of its existence up to the present, San Ildefonso is a predominantly agricultural area. Rice, corn, sugarcane, vegetables and root crops are the primary crops raised by the farmers. Roads leading to the farms and irrigation facilities were constructed by the past administrators to support agriculture. Other support facilities like electricity, local water works system, communication facilities were also provided. "Major Significant Events and Situations Leading to the Present Status of the Municipality"
The most historical event that happened in the town of San Ildefonso is the “Alzamiento de Ambaristo”. This event which was an uprising in Ilocos in bloody protest against Spanish tyranny and oppression was also called the “Basi Revolt of 1807”. Inflamed by the prohibition to make “basi”, the native wine, rebels led by one Ambaristo rose successfully in Laoag, Sarrat, Batac and Piddig, all towns in Ilocos Norte. Then they engaged the Spanish forces at Bantaoay River in San Ildefonso to capture Vigan but they were badly outnumbered and disastrously defeated by well-armed Spanish soldiers. Another significant event was the bloody battle between Ambaristo and one Malong. Ambaristo and his brother Ambalong, both mighty sons of Sarrat, Ilocos Norte, wanted to rule the whole Ilocandia. They gathered their men and armed them with bows and arrows and sharp pointed sticks. They moved south from Sarrat and conquered all the towns they passed by. Malong was another fearless warrior of gigantic field. He was from Pangasinan. He not only wanted to be the ruler of Pangasinan but also of the whole Northern Ilocandia. From his town Binalatongan,now San Carlos City, he mobilized his army to the north conquering also every town he passed by. The two bold and daring leaders with their armies met near the wide and deep river called the Bantaoay River or Rio de Bantaoay in San Ildefonso. They fought bravely. Hundreds after hundreds fell and died. It was so bloody that the water of the River turned red. Ambaristo died in the battle, and was succeeded by his brother. Overpowered Ambalong’s men had to retreat to the mountains. To show them their victory Malong and his men placed Ambaristo in a cage and paraded him as a sign of victory. In September 16, 2009, the LGU celebrated the 200 years anniversary of the Basi Rebolt. However it was no the prohibition of Basi Production but the launching of our OTop “BASI”. As a llivelihood of our constituent. On the same day a S.B. resolution were enacted naming the main barangay road of Gongogong “Kalsada Ambaristo” in honor of Ambaristo the leader of the uprising. "Geographic Location"
The Municipality of San Ildefonso is the sixth Northern most town of the province of Ilocos Sur in Region I. It lies within the North Latitude 17°36’ to 17°38’ and 120°22’ to 120°28’ longitude. This landlock municipality is bounded on the west by the municipality of San Vicente, on the north and northeast by the municipality of Sto. Domingo, and south and southeast by the municipality of Bantay. It is approximately 5 kilometers north of Vigan City – the provincial capital town/ city, 142 kilometers north of San Fernando City, La Union, the Regional Center, and 407 kilometers northwest of Manila. It can be reached using land transportation modes like buses, trucks, cars, jeepneys and others vehicles. " Land Area Classification"
San Ildefonso has a land area of 1,140.8319 hectares square kilometers which is equivalent to 0.44 percent of the total provincial area , per record the cadastral survey and Tax Mapping of the Land Management Sector – DENR about 226.69 hectares or119.87% comprises the urban barangay while 913.8719 hectares or 81.13 percent comprises the rural barangay. Barangay Bungro has the biggest land area while Barangay Busiing sur has the smallest. The entire municipal land is classified as alienable and disposable by the forestry Bureau of the DENR. "Climate"
The municipality belongs to the First type climate which is characterized by two district seasons: wet and dry. The wet season usually starts in May and ends in October, and dry season starts in November to April, although some intermittent passing showers occurs during the later season. As per 1995 records of PAG-ASA – Vigan, the coldest month in the town in February with an average temperature of approximately 25.0 degrees Celsius while the hottest month is May with an average temperature of 28.9 degrees Celsius. The mean relative humidity is 82 millimeters. The municipality is not protected from strong winds because there are no high mountains to protect it. Wind blows in the southeastern direction. An average of 13 typhoons hit and affect the town annually. "Topography and Land Capability"
San Ildefonso generally flat with 94.15% of its area having 0-2.5% slope. Its eastern portion gently slopes with 2.5 to 10%. Its highest spot elevation is 23 meters above sea level which is located in Barangay Bungro. The Bantaoay River and its tributaries drain the municipality. The said river and tributaries which flow towards the west serve as natural drainage, source of irrigation and fishing ground for some farmers.
